The present invention relates to a multi-color printer for simultaneously printing different colors on a full line.
Multi-color printers are known which generally use a thermal printing head, as disclosed in European patent application No. 86 661.
In order to effectuate multi-color printing, line by line, known printers are generally provided with several printing heads disposed one after the other and each provided with an ink ribbon of a different color. Such printers are disclosed, inter alia, for example in U.S. Pat. No. 4,447,818 and in German published application DE-OS No. 3305491, and comprise a transport mechanism for displacing the paper from a printing section to the next. Multi-color printers of that type are expensive to manufacture in view of the high cost of a linear thermo printing head. In addition, accurate superimposition of the diverse colors printed is difficult to achieve and requires particularly severe structural specifications with respect to the paper transport mechanism.
Multi-color printers are also known which are capable of printing line by line with a single printing head and an ink ribbon having portions of different colors arranged one after the other. Those printers, referred to as "harlequin" types, are structurally simpler, but lead however to great waste of ink ribbons, with the result that they are costly to operate.